A fluid flow measurement system

Abstract

The application discloses a fluid flow measurement system, comprising: a pipeline with at least two pipe sections with different diameters and provided with a through hole; a sensor provided on the pipe section with the through hole, the sensor comprising: a diaphragm provided on the side wall of the pipe section, the diaphragm having a groove, the outer bottom surface of the groove being deformable and attached to the through hole; an optical fiber, the first end surface of the optical fiber being arranged corresponding to the groove and forming a reflection cavity together with the inner side surface of the groove, the optical fiber outputting an optical signal which changes along with the deformation of the reflection cavity; and a calculation device connected to the sensor, the calculation device being configured to receive the optical signal and convert the optical signal into a flow signal. The application combines the optical fiber technology with the flow sensor, the sensor does not need to be arranged in the pipeline as a whole, the fluid pressure acts on the reflection cavity, the flow information is transmitted in the form of the optical signal according to the deformation of the reflection cavity, the measurement precision is high, the cleanliness requirement of the measured fluid is low, and the service life of the sensor is long.

Description

Technical Field

[0001] This application relates to the field of flow measurement technology, specifically to a fluid flow measurement system. Background Technology

[0002] The auxiliary power unit (APU) of an aircraft is a small gas turbine engine that can operate independently of the aircraft's main engines. The primary function of the APU is to provide the necessary energy for the aircraft, especially during takeoff and landing. The fuel system must ensure that it supplies fuel to the APU at the flow rate required for normal operation. The APU fuel flow rate is a crucial parameter for analyzing flight test data and assessing the APU's operational status. Therefore, a flow meter needs to be installed at the interface between the fuel system and the APU system to measure the APU fuel supply flow rate under different operating conditions. The fuel flow meter is installed on the fuel supply line between the forward firewall of the APU compartment and the FCU.

[0003] Fluid flow measurement plays a crucial role in industrial production and process control. The complexity of fluid properties, flow states, flow conditions, and sensing mechanisms has resulted in a wide variety of flow measurement instruments, varying in their specialization and price. Flow parameters are essential for industrial production processes, scientific experimental measurement, and various economic calculations, and are a vital component of energy metering.

[0004] Existing flow measurement technologies typically employ turbine flow sensors. Their working principle involves placing a turbine within the fluid being measured. The liquid flow impacts the turbine blades, causing them to rotate. The turbine's rotational speed is directly proportional to the fluid's flow rate. A magnetoelectric conversion device then converts the turbine's rotational speed into a corresponding electrical signal output. However, because the turbine must be installed inside the pipe, the cleanliness of the measured fluid is critical. The fluid's temperature, viscosity, and density significantly affect measurement accuracy, leading to low precision. Furthermore, the rotating components cause bearing wear, impacting the sensor's lifespan. Utility Model Content

[0005] The purpose of this application is to provide a fluid flow measurement system to solve the technical problems of placing turbine sensors inside pipes in the prior art, such as high requirements for the cleanliness of the measured fluid, low measurement accuracy, and sensor wear.

[0006] To address the aforementioned technical problems, embodiments of this application disclose the following technical solutions:

[0007] In a first aspect, embodiments of this application provide a fluid flow measurement system, including:

[0008] A pipe having at least two sections of different diameters and having through holes;

[0009] Sensors are respectively disposed on the pipe section having the through holes, and the sensors include:

[0010] A diaphragm is disposed on the side wall of the pipe section, the diaphragm having a groove, the outer bottom surface of the groove being deformably attached to the through hole;

[0011] An optical fiber, wherein the first end of the optical fiber is disposed corresponding to the groove, and together with the inner side of the groove, it forms a reflective cavity, and the optical fiber outputs an optical signal that changes with the deformation of the reflective cavity;

[0012] A processing device, connected to the sensor, is configured to receive the optical signal and convert the optical signal into a flow signal.

[0013] Preferably, the pipe includes,

[0014] An inlet pipe section, the first end of which is connected to an external fluid, has a first pipe diameter;

[0015] A contraction pipe section, the wide end of which is connected to the second end of the inlet pipe section;

[0016] The throat segment has a first end connected to the narrow end of the constriction segment, and the throat segment has a second diameter; wherein the first diameter is larger than the second diameter.

[0017] Preferably, the sensor includes a first sensor connected to the outside of the inlet pipe section and a second sensor connected to the outside of the throat pipe section.

[0018] Preferably, the through hole includes a first through hole in the inlet pipe section and a second through hole in the throat pipe section.

[0019] Preferably, the first end of the inlet pipe section is provided with a connection part for connecting to an external fluid pipeline.

[0020] Preferably, the pipe is a Venturi tube.

[0021] Preferably, the first end face of the optical fiber is flush with the top surface of the groove opening.

[0022] Preferably, the sensor further includes a substrate disposed on the side of the diaphragm away from the pipe, the substrate having a third through hole corresponding to the groove, and the optical fiber passing through the third through hole.

[0023] Preferably, a collimation tube is provided on the outer side of the optical fiber.

[0024] Preferably, the solving device includes,

[0025] A demodulation device, connected to the sensor, is configured to convert the optical signal into a pressure signal;

[0026] A flow calculation device, connected to the demodulation device, is configured to calculate the flow signal based on the pressure signals corresponding to at least two pipe sections of different diameters.

[0027] Preferably, the demodulation device includes,

[0028] Light source, outputs detection light;

[0029] A circulator has a first port, a second port, and a third port, the first port receiving the probe light, the second port being connected to the second end of the optical fiber, the circulator being configured to transmit the probe light from the first port to the second port, and to transmit the optical signal returning from the second port to the third port;

[0030] A photodetector, connected to the third port, is used to receive the optical signal and generate an electrical signal;

[0031] A signal conditioning component, connected to the photodetector, is used to receive the electrical signal and generate the pressure signal.

[0032] Preferably, the signal conditioning component includes,

[0033] A current-to-voltage converter, connected to the photodetector, is used to receive the electrical signal and generate a preliminary pressure signal;

[0034] An amplifier, connected to the current-to-voltage converter, is used to receive the initial pressure signal and generate an amplified pressure signal;

[0035] A filter, connected to the amplifier, is used to receive the amplified pressure signal and generate a filtered pressure signal.

[0036] An analog-to-digital converter, connected to the filter, is used to receive the filtered pressure signal and generate a discrete pressure signal;

[0037] A digital signal processor, connected to the analog-to-digital converter, is used to receive the discrete pressure signal and generate the pressure signal.

[0038] The beneficial effects of this application are: This application combines optical fiber technology with a flow sensor, so the sensor does not need to be installed as a whole in the pipe. The fluid pressure acts on the reflective cavity, and the flow information is transmitted as an optical signal according to the deformation of the reflective cavity. The measurement accuracy is high, the cleanliness requirement of the measured fluid is low, and the sensor has a long service life. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the pipeline structure in an embodiment of this application;

[0041] Figure 2 This is a schematic diagram of the sensor structure in an embodiment of this application;

[0042] Figure 3 This is a diagram of the computational device architecture in the embodiments of this application;

[0043] Figure 4 This is a diagram showing the relationship between wavelength and reflection coefficient in an embodiment of this application;

[0044] Figure 5 This is a structural diagram of the demodulation device in an embodiment of this application;

[0045] Figure 6 This is an architecture diagram of the signal conditioning component in an embodiment of this application.

[0046] Explanation of reference numerals in the attached drawings: 1. Pipe; 11. Through hole; 111. First through hole; 112. Second through hole; 12. Inlet pipe section; 13. Contraction pipe section; 14. Throat pipe section; 15. Expansion pipe section; 2. Sensor; 21. Diaphragm; 211. Groove; 212. Outer bottom surface of the groove; 22. Optical fiber; 23. Reflection cavity; 24. Substrate; 3. Calculation device; 4. Demodulation device; 41. Light source; 42. Circulator; 421. First port; 422. Second port; 423. Third port; 43. Photodetector; 44. Signal conditioning component; 441. Flow-pressure converter; 442. Amplifier; 443. Filter; 444. Analog-to-digital converter; 445. Digital signal processor; 5. Flow calculation device; a. Fluid flow direction; b. Pressure direction; c. Light source direction. Detailed Implementation

[0047] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "up," "down," "left," and "right" generally refer to up, down, left, and right in the actual use or working state of the device, specifically the drawing directions in the accompanying drawings.

[0048] In this application, unless otherwise expressly specified and limited, the terms "connected," "linked," "stacked," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0049] Those skilled in the art have noted that existing technical solutions employ turbine flow sensors, which work by placing a turbine in the fluid being measured. The liquid flow impacts the turbine blades, causing them to rotate, and the turbine's rotational speed is directly proportional to the fluid's flow rate. However, because the turbine must be installed inside a pipe, the cleanliness of the fluid being measured is critical; the fluid's temperature, viscosity, and density significantly affect measurement accuracy, resulting in low accuracy. Furthermore, rotating parts cause bearing wear, impacting the sensor's lifespan.

[0050] This application combines fiber optic technology with a flow sensor, eliminating the need for the entire sensor to be installed inside the pipeline. Fluid pressure acts only on the reflection cavity, reducing direct contact with impurities in the fluid, lowering the risk of wear and failure caused by impurities, reducing the requirements for fluid cleanliness, reducing mechanical wear, and extending service life.

[0051] The specific implementation methods of this application are illustrated below through examples:

[0052] like Figures 1 to 3 As shown in the figure, this application provides a fluid flow measurement system, including:

[0053] Pipeline 1 has at least two sections of different diameters and is provided with through holes 11;

[0054] Sensor 2 is disposed on a pipe section having through hole 11. Sensor 2 includes:

[0055] A diaphragm 21 is disposed on the side wall of the pipe section. The diaphragm 21 has a groove 211, and the outer bottom surface 212 of the groove 211 is deformably attached to the through hole 11.

[0056] Optical fiber 22, with its first end facing corresponding to the groove 211, forms a reflecting cavity 23 with the inner side of the groove 211. The optical fiber 22 outputs an optical signal that changes with the deformation of the reflecting cavity 23.

[0057] The calculation device 3 is connected to the sensor 2. The calculation device 3 is configured to receive optical signals and convert the optical signals into flow signals.

[0058] This application combines fiber optic technology with a flow sensor, so that the flow information is converted into an optical signal at the transmitter of the fiber optic cable 22 after passing through the sensor 2, and then transmitted to the calculation device 3 through the fiber optic cable 22, realizing long-distance transmission and facilitating the networked management of the sensor 2. The calculation device 3 can be integrated into a host computer, and one host computer can manage and monitor multiple sensors 2. This maintains the advantages of the original sensor and incorporates the anti-interference advantage of the fiber optic transmission line.

[0059] Specifically, the fluid pressure inside the pipe section will be transmitted through the through hole 11 along the pressure direction b to the outer bottom surface 212 of the groove 211 of the diaphragm 21. Since the outer bottom surface 212 of the groove 211 is deformable, it will deform under pressure. The greater the pressure, the greater the deformation.

[0060] The inner surface of diaphragm 21 serves as the reflecting surface on one side of the reflecting cavity 23, and the first end face of optical fiber 22 serves as the reflecting surface on the other side of the reflecting cavity. The reflecting cavity 23 is a Fabry-Perot cavity with these two reflecting surfaces. The reflecting cavity 23 deforms under pressure, such as... Figure 4 As shown, changes in the cavity length alter the propagation characteristics of light within the cavity, thus changing its interference spectrum. The optical signal output from fiber 22 changes with the deformation of the reflecting cavity 23, converting pressure changes into changes in the optical signal. This is achieved by monitoring... Figure 4 The variation of the curve S with wavelength can be used to demodulate the cavity length, thereby enabling pressure measurement.

[0061] More specifically, when the incident light travels along the light source direction c through the optical fiber 22 to the sensor 2 and reaches the reflecting cavity 23, due to the reflectivity of the diaphragm 21 and the first end face of the optical fiber 22, the light will reflect back and forth between the two reflecting surfaces of the reflecting cavity 23, resulting in multi-beam interference and producing alternating bright and dark interference fringes. Preferably, the diaphragm 11 is a single-crystal silicon diaphragm, and the reflectivity of its inner surface and the end face of the optical fiber 22 is very low. Therefore, except for the light directly reflected from the inner surface of the diaphragm 21 and the light directly reflected from the first end face of the optical fiber 22, which have relatively high intensities, the intensities of other multiple reflections are very weak and have little impact on the overall interference effect, which can be ignored. The multi-beam interference can be approximated as a two-beam interference model. The intensity of its reflection spectrum can be expressed as:

[0062]

[0063] in, This indicates the reflection intensity of the inner surface of diaphragm 21. This represents the reflection intensity at the first end face of optical fiber 22. This represents the refractive index of the reflecting cavity 23. This indicates the cavity length of the reflecting cavity 23. Indicates the wavelength of light. This represents the phase difference caused by half-wave loss. It should be noted that because the reflecting cavity is fitted to pipe 1, its shape is not a regular rectangle; in actual scenarios, it is closer to an arc. The cavity length here... This refers to the distance between the two reflecting surfaces of the reflecting cavity 23.

[0064] This application selects a silicon-sensitive diaphragm as the sensing element of sensor 2. Under external pressure, the diaphragm 21 will deform, causing a change in the cavity length L. The deformation formula of diaphragm 21 is:

[0065]

[0066] in, This represents the deformation of diaphragm 21. Represents Poisson's ratio. This indicates the pressure exerted on diaphragm 21. Indicates the elastic modulus. This indicates the thickness of the bottom surface of groove 211. Indicates the radius of the groove. This represents the distance from any point on the bottom surface of groove 211 to the center of the groove;

[0067] According to the deformation formula of diaphragm 21, the maximum elastic deformation occurs at the center of the groove, that is... At this point, the deformation of the diaphragm center along the fiber axis Satisfy the following formula:

[0068]

[0069] When compressed, the central deformation of the diaphragm This is the change in cavity length, cavity length When changes occur, the intensity of the reflection spectrum changes accordingly. Therefore, by analyzing the changes in the reflection spectrum, the change in cavity length can be demodulated, thereby obtaining pressure information.

[0070] In a preferred embodiment, pipe 1 includes,

[0071] Inlet pipe section 12, with its first end connected to an external fluid, has a first pipe diameter;

[0072] Contraction pipe section 13, the wide end of contraction pipe section 13 is connected to the second end of inlet pipe section 12;

[0073] The throat section 14 has a first end connected to the narrow end of the contraction section 13, and the throat section 14 has a second diameter; wherein the first diameter is larger than the second diameter.

[0074] Specifically, pipe 1 includes inlet pipe section 12, contraction pipe section 13 and throat pipe section 14. The flow rate is measured by creating a pressure difference in the fluid through changes in pipe diameter.

[0075] According to Bernoulli's principle, when a fluid is in steady flow, the sum of the kinetic energy, potential energy, and pressure energy per unit volume is constant. When the fluid flows in from the inlet pipe section 12 along the fluid direction a, its first pipe diameter has a large cross-sectional area. As the fluid enters the contraction pipe section 13, the pipe diameter gradually decreases, the cross-sectional area decreases, and the flow velocity increases. At the throat pipe section 14, its second pipe diameter has a small cross-sectional area, and the flow velocity is the largest. Due to the change in flow velocity, according to Bernoulli's equation, the pressure in different pipe sections will change, generating a pressure difference at the branch. Based on the specific relationship between the pressure difference and the fluid flow rate, the fluid flow rate can be calculated.

[0076] In a preferred embodiment, sensor 2 includes a first sensor connected to the outside of inlet pipe section 12 and a second sensor connected to the outside of throat pipe section 14.

[0077] Specifically, the first sensor and the second sensor respectively sense the pressure of the inlet pipe section 12 and the throat pipe section 14. The first sensor outputs a first optical signal, and the demodulation device 4 of the calculation device 3 outputs a first pressure signal to characterize the pressure of the inlet pipe section 12 based on the first optical signal. The second sensor outputs a second optical signal, and the demodulation device 4 of the calculation device 3 outputs a second pressure signal to characterize the pressure of the throat pipe section 14 based on the second optical signal. The flow calculation device 5 of the calculation device 3 obtains the pressure difference based on the first pressure signal and the second pressure signal, and then calculates the flow rate of the fluid.

[0078] In a preferred embodiment, the through hole 11 includes a first through hole 111 provided in the inlet pipe section 12 and a second through hole 112 provided in the throat pipe section 14.

[0079] Specifically, through holes are provided in the inlet pipe section and the throat pipe section respectively. The pressures in the inlet pipe section 12 and the throat pipe section 14 are different. The pressure in the inlet pipe section 12 acts on the first sensor through the first through hole 111, and the pressure in the throat pipe section 14 acts on the second sensor through the second through hole 112.

[0080] In a preferred embodiment, the first end of the inlet pipe section 12 is provided with a connection for connecting to an external fluid pipeline.

[0081] Specifically, the connection part has a threaded structure, and the inlet pipe section 12 is connected to the fluid pipeline through the threaded structure.

[0082] In a preferred embodiment, pipe 1 is a Venturi pipe.

[0083] Specifically, pipe 1 also includes an expansion section 15, which connects to the second end of the throat section 14. The Venturi tube consists of an inlet section 12, a contraction section 23, a throat section 14, and an expansion section 15. When fluid flows through the Venturi tube, according to Bernoulli's principle, in steady flow, the sum of the kinetic energy, potential energy, and pressure energy per unit volume is constant. In the inlet section 12, the fluid has a large cross-sectional area and a low velocity. As it enters the contraction section 13, the pipe diameter gradually decreases, the velocity increases, and the pressure decreases; at the throat section 14, the velocity reaches its maximum, and the pressure is minimum. By measuring the pressure difference between the inlet section 12 and the throat section 14, the flow calculation device 5 calculates the fluid flow rate using the determined relationship between the pressure difference and the flow rate.

[0084] In a preferred embodiment, the first end face of the optical fiber 22 is flush with the top surface of the groove 211.

[0085] Specifically, since the diaphragm 21 is a single-crystal silicon diaphragm with a groove 211, the initial parameters of the groove 211 are determined. When the first end face of the optical fiber 22 is flush with the top surface of the groove 211, the initial parameters of the reflection cavity 23 can be easily determined, which facilitates calculation and improves calculation accuracy. Of course, in other embodiments, the first end face of the optical fiber 22 can also be inserted into the groove 211 to obtain the reflection cavity 23, as long as the initial parameters of the reflection cavity 23 can be obtained.

[0086] In a preferred embodiment, the sensor 2 further includes a substrate 24, which is disposed on the side of the diaphragm 21 away from the pipe 1. The substrate 24 has a third through hole corresponding to the groove 211, and the optical fiber 22 passes through the third through hole.

[0087] Specifically, sensor 2 is a silicon-glass fiber optic FP pressure sensor. The sensor head is manufactured using micro-electro-mechanical systems (MEMS) technology and anodic bonding technology, and includes a diaphragm 21 and a substrate 24. The diaphragm 21 is a single-crystal silicon diaphragm with grooves, and the substrate 24 is a BF33 type high borosilicate glass substrate.

[0088] In a preferred embodiment, a collimation tube is provided on the outer side of the optical fiber 22.

[0089] Specifically, sensor 2 also includes a collimating tube and an optical fiber 22. The collimating tube is a capillary glass tube, and the optical fiber 22 is a single-mode fiber (SMF). After the optical fiber 22 is inserted into the glass tube for collimation, it is then inserted into the third through-hole of the substrate 24, aligning the first end face of the optical fiber 22 with the diaphragm 21 of sensor 2. At this point, a reflecting cavity 23 is formed between the inner surface of the diaphragm 21 and the first end face of the optical fiber 22, thus constituting a complete sensor 2. When the diaphragm 21 senses external pressure, it causes a change in the cavity length of the reflecting cavity 23, which in turn causes a change in its interference spectrum. By demodulating the cavity length using spectral information, pressure measurement can be achieved.

[0090] In a preferred embodiment, the solving device 3 includes,

[0091] Demodulation device 4 is connected to sensor 2 and is configured to convert optical signals into pressure signals;

[0092] The flow calculation device 5 is connected to the demodulation device 4. The flow calculation device 5 is configured to calculate the flow signal based on the pressure signals corresponding to at least two pipe sections with different diameters.

[0093] Specifically, sensor 2 transmits optical signals to demodulation device 4 via optical fiber 22. The optical path connector of this application is directly spliced ​​with optical fibers. Demodulation device 4 and flow calculation device 5 can be integrated into the host computer or flow calculation device 5 can be integrated into the host computer. Demodulation device 4 transmits pressure signals to the host computer via cable.

[0094] Specifically, in this embodiment, the principle by which the flow calculation device 5 can calculate and obtain the flow signal based on the pressure signal is as follows:

[0095] Assuming the fluid flows from inlet pipe section 12 to throat pipe section 14, the energy conservation equation for steady fluid flow is:

[0096]

[0097]

[0098] in, Indicates pressure. This indicates the pressure in inlet pipe section 12. This indicates the pressure in throat segment 14. Indicates the density of the fluid. Indicates the velocity of the fluid. This indicates the velocity of the fluid in inlet pipe section 12. This indicates the velocity of the fluid in the throat section 14. Represents gravitational acceleration. Indicates position height. This indicates the height of the fluid at the inlet pipe section 12. This indicates the position and height of the fluid in the throat section 14.

[0099] The above formula represents the kinetic energy per unit volume of fluid at different locations during steady flow of an ideal fluid. gravitational potential energy and pressure The sum of them is a constant.

[0100] Because the fluid flows horizontally in pipe 1, the fluid position at inlet pipe section 12 is at a height of and the height of the fluid at the throat section 14 Since they are the same, it can be deduced that...

[0101]

[0102] By rearranging, we can obtain

[0103]

[0104] According to the flow equation

[0105]

[0106] in This represents the cross-sectional area of ​​inlet pipe section 12. This represents the cross-sectional area of ​​the throat segment 14. To represent the flow rate, we can obtain...

[0107]

[0108] Bring it into We can obtain,

[0109]

[0110] After simplification,

[0111]

[0112] Therefore, calculate the flow. The formula can be expressed as,

[0113]

[0114] The flow calculation device 5 calculates the flow rate based on the known density of the fluid. The known cross-sectional area of ​​inlet pipe section 12 Cross-sectional area of ​​throat segment 14 And the pressure of the inlet pipe section 12 output through the demodulation device 4. Pressure of throat segment 14 The fluid flow rate can then be calculated. .

[0115] In a preferred embodiment, such as Figure 5 As shown, the demodulation device 4 includes,

[0116] Light source 41 outputs probe light;

[0117] Circulator 42 has a first port 421, a second port 422 and a third port 423. The first port 421 receives probe light, the second port 422 is connected to the second end of optical fiber 22, and circulator 42 is configured to transmit probe light from the first port 421 to the second port 422 and transmit the optical signal returned from the second port 422 to the third port 423.

[0118] Photodetector 43 is connected to third port 423 and is used to receive optical signals and generate electrical signals;

[0119] The signal conditioning component 44 is connected to the photodetector 43 and is used to receive electrical signals and generate pressure signals.

[0120] Specifically, the light source 41 is a monochromatic light source, and the output probe light serves as an information carrier. The first port 421 of the circulator 42 receives the probe light emitted by the light source 41 and then transmits it to the second port 422, allowing the probe light to enter the optical fiber 22. After the probe light is transmitted to the optical fiber 22, the reflecting cavity 23 deforms due to pressure. The change in its cavity length alters the propagation characteristics of light within the cavity, thereby changing its interference spectrum. The optical fiber 22 returns the light signal that changes with the deformation of the reflecting cavity 23 from the second port 422, and is transmitted by the circulator 42 to the third port 423.

[0121] The photodetector 43 converts the received light signal into an electrical signal based on the photoelectric effect. The signal conditioning component 44 receives the electrical signal generated by the photodetector 43 and converts it into a pressure signal that reflects the fluid pressure.

[0122] In a preferred embodiment, such as Figure 6 As shown, the signal conditioning component 44 includes,

[0123] The current-to-voltage converter 441 is connected to the photodetector 43 and is used to receive electrical signals and generate preliminary pressure signals.

[0124] Amplifier 442 is connected to current-to-voltage converter 441 and is used to receive the initial pressure signal and generate an amplified pressure signal.

[0125] Filter 443 is connected to amplifier 442 and is used to receive the amplified pressure signal and generate the filtered pressure signal.

[0126] The analog-to-digital converter 444 is connected to the filter 443 and is used to receive the filtered pressure signal and generate a discrete pressure signal.

[0127] The digital signal processor 445, connected to the analog-to-digital converter 444, is used to receive discrete pressure signals and generate pressure signals.

[0128] Specifically, the current-to-voltage converter 441 converts the electrical signal received from the photodetector 43 into a preliminary pressure signal based on physical effects (such as piezoresistive and piezoelectric effects). The amplifier 442 amplifies the received preliminary pressure signal, and the filter 443 filters the amplified pressure signal. The analog-to-digital converter 444 converts the filtered continuous pressure signal into a discrete pressure signal. The digital signal processor 445 processes the discrete pressure signal, such as removing outliers, smoothing the data, calculating the corresponding pressure value, and generating the final pressure signal.

[0129] The fluid flow measurement system provided in this application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A fluid flow measurement system, characterized in that, include, Pipe (1) having at least two sections of different diameters and having through holes (11); Sensors (2) are respectively disposed on the pipe section having the through hole (11), and the sensor (2) includes, A diaphragm (21) is disposed on the side wall of the pipe section. The diaphragm (21) has a groove (211), and the outer bottom surface (212) of the groove (211) is deformably attached to the through hole (11). An optical fiber (22) is provided with its first end facing the groove (211) and together with the inner side of the groove (211) to form a reflective cavity (23). The optical fiber (22) outputs an optical signal that changes with the deformation of the reflective cavity (23). The calculation device (3) is connected to the sensor (2) and is configured to receive the optical signal and convert the optical signal into a flow signal.

2. The fluid flow measurement system according to claim 1, characterized in that, The pipeline (1) includes, An inlet pipe section (12) has a first end connected to an external fluid and has a first pipe diameter. A contraction pipe section (13), the wide end of which is connected to the second end of the inlet pipe section (12); The throat segment (14) has a first end connected to the narrow end of the constriction segment (13), and the throat segment (14) has a second diameter; wherein the first diameter is larger than the second diameter.

3. The fluid flow measurement system according to claim 2, characterized in that, The sensor (2) includes a first sensor (2) connected to the outside of the inlet pipe section (12) and a second sensor (2) connected to the outside of the throat pipe section (14).

4. The fluid flow measurement system according to claim 2, characterized in that, The through hole (11) includes a first through hole (111) provided in the inlet pipe section (12) and a second through hole (112) provided in the throat pipe section (14).

5. The fluid flow measurement system according to claim 2, characterized in that, The first end of the inlet pipe section (12) is provided with a connecting part for connecting to an external fluid pipeline.

6. The fluid flow measurement system according to claim 1, characterized in that, The pipe (1) is a Venturi pipe.

7. The fluid flow measurement system according to claim 1, characterized in that, The first end face of the optical fiber (22) is flush with the top surface of the groove (211).

8. The fluid flow measurement system according to claim 1, characterized in that, The sensor (2) further includes a substrate (24), which is disposed on the side of the diaphragm (21) away from the pipe (1). The substrate (24) has a third through hole corresponding to the groove (211), and the optical fiber (22) passes through the third through hole.

9. The fluid flow measurement system according to claim 1, characterized in that, The outer side of the optical fiber (22) is provided with a collimation tube.

10. The fluid flow measurement system according to claim 1, characterized in that, The calculation device (3) includes, A demodulation device (4) is connected to the sensor (2), and the demodulation device (4) is configured to convert the optical signal into a pressure signal; A flow calculation device (5) is connected to the demodulation device (4), and the flow calculation device (5) is configured to calculate the flow signal based on the pressure signals corresponding to at least two pipe sections with different diameters.

11. The fluid flow measurement system according to claim 10, characterized in that, The demodulation device (4) includes, Light source (41), outputs probe light; A circulator (42) has a first port (421), a second port (422) and a third port (423), the first port (421) receiving the probe light, the second port (422) being connected to the second end of the optical fiber (22), the circulator (42) being configured to transmit the probe light from the first port (421) to the second port (422) and transmit the optical signal returning from the second port (422) to the third port (423). A photodetector (43) is connected to the third port (423) for receiving the optical signal and generating an electrical signal. The signal conditioning component (44) is connected to the photodetector (43) and is used to receive the electrical signal and generate the pressure signal.

12. The fluid flow measurement system according to claim 11, characterized in that, The signal conditioning component (44) includes, A flow-voltage converter (441) is connected to the photodetector (43) for receiving the electrical signal and generating a preliminary pressure signal; An amplifier (442) is connected to the current-to-voltage converter (441) for receiving the initial pressure signal and generating an amplified pressure signal; A filter (443) is connected to the amplifier (442) and is used to receive the amplified pressure signal and generate a filtered pressure signal. An analog-to-digital converter (444) is connected to the filter (443) and is used to receive the filtered pressure signal and generate a discrete pressure signal. A digital signal processor (445), connected to the analog-to-digital converter (444), is used to receive the discrete pressure signal and generate the pressure signal.

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